Think it's cold now? 140M in U.S. will shiver at 0 degrees -- or lower

Updated 5:30 p.m.(CNN) -- If you thought the snow was bad, just wait for the cold and ice.

"Don't put your tongue on
a flagpole today," Connecticut Gov. Dannel Malloy said Friday, advice
that may prove useful over the long term.

"We're going to see a
warm-up, and then we're going to see another cold snap," he said. "This
may be something that we're dealing with for the next 60 days or so."

The National Weather
Service offered similar, if less folksy, admonitions: "Very cold
temperatures and dangerous wind chills are moving in behind the system,"
the service said Friday. "Some of the coldest air of the year should
arrive by the weekend over the northern tier of the country."

Between Friday and next
Wednesday, nearly 140 million Americans -- nearly half the nation --
will experience temperatures dipping to 0 degrees Fahrenheit or below,
according to a CNN calculation.

That may include lows in the -20s Fahrenheit across North Dakota and Minnesota, with wind chills approaching -50, the weather service said.

In Minnesota, which could
see its lowest temperatures in a decade, Gov. Mark Dayton canceled
Monday's classes in public schools across the state.

The combination of cold
and gusts exceeding 30 mph was expected to lower wind chill temperatures
to near zero in the nation's capital and to 45 below in northern Maine.

And another storm is
forming that will bring blizzard conditions to North Dakota and parts of
South Dakota and Minnesota on Friday night and Saturday, the weather
service said.

Though temperatures may rise temporarily in the Midwest and Northeast, they are expected to reverse course Sunday and Monday.

A new storm will likely drop snow Sunday and Monday on St. Louis, Indianapolis, Cincinnati, Cleveland, Pittsburgh and Buffalo.

Parts of the Midwest could see temperatures not recorded in 15 to 20 years.

In the Windy City, the
arctic blast could be the coldest in 18 years, with subzero temperatures
from Sunday evening until Wednesday.

The arctic air will dive southward Monday and Tuesday, carrying zero-degree cold as far south as Nashville.

In the Northeast, the
heavy snow that upended routines for about a third of the nation's
residents on Friday had tapered off by noon, but snow drifts were
complicating the cleanup, in some cases requiring replowing of streets
that had already been cleaned.

New York was draped Friday in a near-10-inch layer of white, but that didn't faze some residents.

"A lot of people are walking, and some were even running in Central Park," said CNN iReporter Matthew Burke, who snapped a photograph of the entrance to the park at Fifth Avenue and 72nd Street.

"It's freezing," he said. "I had three layers on, and I was still cold."

It was not expected to
get better. Temperatures in Central Park were predicted to drop to zero
Friday night for the first time since January 1994.

The snowfall abated
early Friday in the nation's capital and was expected to stop in the
afternoon in Boston, which got nearly 15 inches.

North of Boston, residents of Topsfield were inundated with nearly 2 feet of snow.

Weather knocks out flights

Across the country, the weather wreaked havoc on airlines' flight schedules.

FlightAware.com,
which tracks cancellations due to weather and mechanical problems, said
that more than 2,400 flights had been canceled for Friday within, into
or out of the United States. That's after more than 2,600 U.S. flights
were canceled Thursday.

Though the temperature
in Las Vegas was 52 degrees -- above zero -- passengers there were also
feeling the storm's sting. Long lines formed inside McCarran
International Airport at the counters for Southwest Airlines, which had
canceled many of its flights from Chicago. The airline carries 40% of
the airport's passengers, according to Chris Hayes, an airport
spokesman.

"We are doing everything
possible to get back up and running as soon as possible," Southwest
Airlines spokesman Dan Landson told CNN.

Flights resumed by late
Friday morning in much of New England, though delays were common, and
ticket holders were urged to check with their airlines.

Barb Plooster had
planned to fly Friday from Erie, Pennsylvania, to Grand Rapids,
Michigan, but her flight was canceled. She told CNN affiliate WICU
that she was on the phone with United Airlines for five hours trying to
find a way to get home but has concluded that she will have to wait
until Monday. "We got a warm place to stay, get to visit the kids, the
grandkids, so it's OK," she said.

Here's a breakdown of what to expect where:

New York and Long Island

In New York City,
Friday's high was predicted to be 18 degrees, and the temperature was
expected to go below zero by nightfall, Mayor Bill de Blasio said.

He urged anyone who
might see a homeless person to call 311, "and an outreach team will go
out immediately to help that individual."

But the newly sworn-in
mayor -- who shoveled in front of his home in Brooklyn on Friday morning
before handing off the duty to his 16-year-old son, Dante -- praised
his team for their work.

"I'd give everyone an A" for effort and effectiveness, he said, but noted that their work was not over.

"Ask again in a few hours," he said. "This is an hour-to-hour thing."

New York had gotten nearly 10 inches of snow by the time it abated late Friday morning, de Blasio said.

Sanitation workers were on 12-hour shifts to clear the city's 6,200 miles of roadways, he said.

Flight operations
resumed late Friday morning at John F. Kennedy International Airport;
they were continuing -- despite hundreds of cancellations -- at
LaGuardia Airport and Newark Liberty International Airport.

Single-digit temperatures were predicted for Saturday morning.

New York City public schools were closed Friday.

The weather had its fans. In Rochester, New York, CNN iReporter Blake Sampson, 29, took a picture from his apartment window. "I grew up in Minnesota, so I'm used to it," he said. "I like how quiet things get when there is a fresh blanket of snow."

Massachusetts

That blanket covered
Boston, which expected to see 10 to 18 inches of snow and temperatures
as low as 6 degrees below zero by Friday night.

But limited flights were continuing into and out of Boston's Logan International Airport.

The state's emergency management agency predicted up to 2 feet of snow on parts of the North Shore, South Shore and Cape Cod.

Students in scores of school districts were told to stay home Friday.

"I guess Mother Nature
wanted to give me one more gift," Boston Mayor Thomas Menino said
Thursday, one of his last days in the office he has held since 1993.

Chicago and points beyond

The cold could affect NFL playoff games this weekend:

Saturday's game between
the Kansas City Chiefs and the Indianapolis Colts will be played at
around 32 degrees, but those inside the Colts' dome should be a little
warmer.

On Saturday night, the
New Orleans Saints will play the Philadelphia Eagles in the City of
Brotherly Love, where the forecast was for 24 degrees and clear skies at
kickoff.

In Wisconsin, the Green
Bay Packers will give a cold welcome to the San Francisco 49ers on
Sunday, when wind chills could be -30.

"This is not the norm,"
Packers head coach Mike McCarthy told reporters Friday. "It's obviously
challenging mentally and physically, and this will definitely be the
case Sunday."

When the San Diego
Chargers face off Sunday afternoon against the Cincinnati Bengals, a
snow storm may be moving through the area.

The U.S. weather has had
international implications, too: All meetings were canceled Friday at
the United Nations headquarters complex on New York's East Side.